Writing instrument



y 9, 1969 5. G. LARSON 3,458,267

V WRITING INSTRUMENT Filed Oct. 50. we?

I INVENTOR GEORGE a. LARSON United States Patent U.S. Cl. 401213 9Claims ABSTRACT OF THE DISCLOSURE A writing instrument characterized bya barrel forming elongated plastic tube having identical portions ofreduced cross section at opposite ends thereof upon which a plug coverand a barrel nose, respectively, are received in telescoping relation,the plug cover being telescoped over the post forming hollow open endand having self-threading features so as to provide passageways betweenthe inside wall of the plug cover and the post when the cover is screwedonto the post, which passageways lead to the exterior of the barrelthrough slots at the inner end of the cover and provide a vent formingpassageway from the interior of the barrel, and the barrel nose having aball point assembly mounted therein and a snap-on plastic cap.

This invention relates to writing instruments and is more particularlyconcerned with improvements in a pen structure of the ball point typewhich includes an open ended elongate ink containing barrel with specialprovisions for mounting a barrel nose and an associated ball point onone end of the barrel and a plug cover on the other end.

It is a general object of the invention to provide an improved ballpoint pen structure which can be economically produced for marketing ata relatively low price and which will operate in a satisfactory mannerwithout clogging or drying out of the writing fluid.

It is a more particular object of the invention to pro vide a penstructure which comprises an elongate, open ended barrel forming anink-containing member with the top forming end thereof vented throughpassageways between the walls of a hollow end post on the barrel and atelescoping cap, the latter having a self-threading screw on connectionwith the barrel end post.

It is a further object of the invention to provide a pen structure whichcomprises an elongated tubular barrel formed of plastic material andhousing an ink supply with the barrel being open at the top forming endand having a hollow post which is of reduced diameter and on which aplug cover is screwed in telescoping relation and provided with ventforming passageways which extend to a recess formed in the inner edgethereof above a tapered shoulder at the top of the barrel and which opento the atmosphere.

Another object of the invention is to provide a pen structure whichincludes a barrel forming tube with end formations of reduced crosssection which are identical and which enable a ball point assembly to bemounted on either end formation and a plug cap which may haveself-threading, telescoping engagement with either end formation.

These and other objects and advantages of the invention will be apparentfrom a consideration of the pen structure which is shown by way ofillustration in the accompanying drawings wherein:

FIGURE 1 is a perspective view of a pen which embodies the principalfeatures of the invention, the pen being shown to an enlarged scale;

FIGURE 2 is an exploded elevational view to a still larger scale withthe pen structure in partly disassembled 3,458,267 Patented July 29,1969 ice condition, with portions broken away, and with the cap in crosssection;

FIGURE 3 is a longitudinal section taken on the line 3-3 of FIGURE 2, toan enlarged scale, showing the screw-on plug cover structure;

FIGURE 4 is a longitudinal section taken on the line 4--4 of FIGURE 2 toan enlarged scale, with the cap Omitted; and

FIGURE 5 is a cross-section taken on the line 5-5 of FIGURE 2, to astill larger scale.

The pen structure 10 (FIGURE 1) which is illustrative of the presentinvention is a ball point type having an elongate tubular member forminga barrel 11 in which there is an axial compartment 12 (FIGURE 2) adaptedto receive a suitable writing fluid. The barrel is symmetrical about atransverse axis and receives at one end a screw on plug cover 1 4 and atthe other end the barrel nose 15 in which a writing ball assembly 16 ismounted. The nose 15 has a circumferential rib 17 for cooperation withan internal groove 18 in a cap forming member 26, the marginal portionof which is slit at 21 to provide the cap 20 with a snap-on feature. Aspring metal clip 22 having a split mounting sleeve 23 is adapted to beadjustably positioned on the barrel 11 to complete the unit.

The barrel 11 comprises an elongate extruded plastic tube with aninternal axial bore 12 forming an ink-receiving compartment. The ends ofthe tube are machined in an identical manner to provide relatively shortlengths or end portions 24 and 24 or reduced diameter which areconnected to the main body of the tube at external shoulders 25 and 25,the latter tapering in the direction of the longitudinal axis and theends of the tube at an angle of approximately The barrel nose 15 which,in the illustrated form of the pen, is mounted on the barrel end portion24, is formed of a suitable plastic with an axial bore 26 terminating atthe inner or upper end in a tapered end edge 27 with the tapercorresponding to that of the shoulder 25 on the barrel 11 so as to seatthereon, the external diameter at the inner end being less than thecorresponding dimension of the barrel body so as to accommodate the cap20. At the outer end of the nose -15 the bore 26 is reduced in diametersomewhat and tapers at 28 to an inwardly projecting circumferential rib30 which is spaced inwardly a slight distance from the end of the nose.The bore 26 is provided with a plurality of axially extending ribs 31for adjusting the fit when the nose is forced onto the barrel endformation 24. The external surface of the nose 15 is tapered somewhatinwardly in the direction of the point receiving end thereof.

The writing ball assembly comprises a metal body or point 32 oftruncated cone shape with an axial bore and closed at the tip end by awriting ball 33 of suitable material and having a stem forming portion34 at the other end. The stem portion 34 is adapted to telescope withinthe bore 26 of the barrel nose and has an external diametercorresponding approximately to or slightly greater than the internaldiameter of the rib 30 SO that the latter fits snugly thereon and formsa ring seal on the stem 34 which prevents leakage.

The plug cover 14, which is formed of a material harder than that of thebarrel 11, has an internal bore 35 (FIGURE 3) of greater diameter thanthe external diameter of the plug forming end section 24' on the barrel11. The bore 35 is provided with a spiral thread formation 36 of theself-cutting type which enables the cover to be screwed onto the plug24' and to cut a cooperating thread groove in the surafce of the latterupon initial assembly. The bore 35 is closed at the outer or upper endand at the inner end terminates at the inner edge of a tapered endsurface 37 which is adapted to seat on the shoulder 25'. A plurality ofcircumferentially spaced, relatively shallow venting slots 38 areprovided in the surface 37 so as to connect the spaces between thethread formations with the exterior of the pen and provide a passagewayfrom the interior of the barrel 11 to the atmosphere outside of thesame. The plug cover 14 has an external rib 40 for cooperation with the'internal groove .18 on the cap member 20 so as to hold the cap on thatend of the pen when the point is uncovered for use and the cap 20 istelescoped over the plug cover 14.

The cap 20 is formed of resilient plastic or the like with the margin atthe open end slotted at 21 to provide a series of spring fingers havingan internal group 18 for snap-on engagement with the external shoulderor rib 17 on the barrel nose 15 and the rib 40 on the plug cover 14. Aplurality of radially and axially extending, circumferentially spacedrectangular rib formations 41 of relatively short length are provided atthe bottom of the cap which form a seat for the point 32 with the lengthof the ribs 41 being such as to limit the axial movement of the cap 20by engaging the end of the plug cover 14 when it is placed thereon andthe rib 40 is engaged in the groove .18.

While particular materials and specific details of construction havebeen referred to in describing the form of the pen structure which isillustrated, it will be understood that other materials and differentstructural details of an equivalent nature may be resorted to within thespirit of the invention.

I claim:

1. A writing instrument comprising an elongate barrel for housing awriting fluid with the upper end thereof open, said barrel having aportion at its upper end with a reduced cross sectional dimension so asto provide a hollow post formation extending from an external shoulderat the upper end of said barrel, and a plug cover adapted to telescopeover said post formation, and said plug cover having an internal threadformation for cutting a cooperating thread groove in said post formationwhen screwed thereon and providing connecting passageways which are incommunication with the interior of said hollow post formation and theexterior of the pen so as to form a vent for said barrel when said plugcover is seated against the external shoulder on the barrel.

2. A writing instrument comprising an elongate barrel for housing awritting fluid, said barrel being characterized by a section ofrelatively rigid plastic tubing having at its opposite endssubstantially identical portions of reduced diameter constituting postformations which are joined to the body of the tube by external shoulderformations, a plug cover recessed to enable it to be telescoped overeither one of said end post formations so as to close the one end of thebarrel, said plug cover having internal means for connection with saidend post formation and forming passageways which are in communicationwith the interior of said end post formation and the exterior of the penso as to form a vent for said barrel, a barrel nose also recessed totelescope over either one of said end post formations and having a penpoint assembly mounted therein with axial passageways connecting the penpoint with the interior of the barrel for passage of the writing fluid.

3. A writing instrument comprising an elongate barrel for housing awriting fluid, said barrel being characterized by a section ofrelatively rigid plastic tubing having at its opposite ends portions ofreduced diameter constituting post formations which are joined to thebody of the tube by external shoulder formations, a plug cover adaptedto telescope over either one of said post formations so as to close theone end of the barrel, said plug cover having passageways which are incommunication with the exterior of the pen so as to form a vent for saidbarrel, a barrel nose also adapted to telescope over either one of saidpost formations and having a pen point assembly mounted therein withpassageways connecting the pen point with the interior of the barrel forpassage of the writing fluid, and said plug cover having an internalbore which is of greater diameter than the external diameter of the postformation and a thread formation in said bore which is adapted to cut acooperating thread groove on the post formation when screwed thereon.

4. A writing instrument as set forth in claim 3, and said plug coverhaving its inner end seated on the external shoulder formation where thepost formation joins the body of the tube and having recesses in saidinner end forming part of said venting passageways.

5. A writing instrument as set forth in claim 2, and said plug coverhaving an internal bore of greater diameter than the external diameterof said post formation and a male thread formation in said bore which isarranged to cut a cooperating female thread formation on said postformation when screwed thereon, and said thread formations providingwhen engaged passageways between the inner wall of the plug cover andthe outer wall of the post formation which cooperate with slots in theend edge of said plug cover to form the vent for said barrel.

6. A writing instrumentas set forth in claim 2 and said pen pointassembly including a truncated cone shaped body with an axial stemformation extending at the larger end which has a cross sectionaldiameter less than the internal diameter of said barrel nose andtelescopes Within 'the outer end of the barrel nose and said barrel nosehaving an internal shoulder adjacent the outer end thereof which snuglyengages in sealing relation the outer surface of said stem formation.

7. A writing instrument as set forth in claim 2 and said barrel nosehaving an axial bore which is somewhat larger in diameter than theexternal diameter of the end post formation on the barrel, and axiallyextending internal ribs in the bore of said barrel nose which engage theexternal surface of the end post formation so as to insure a tight fitupon assembly.

8. A writing instrument comprising an elongate barrel for housing awriting fluid with the opposite ends having a plug cover and a barrelnose and point assembly, respectively, a snap-on cap having the marginat the open end slotted and provided with an internal groove forselective snap-on engagement with cooperating external ribs pro vided onthe barrel nose and the plug cover respectively, and said cap havingaxially extending, circumferentially spaced ribs in the closed endthereof which provide a seat for the point when the cap is telescopedover'the barrel nose.

9. A writing instrument as set forth in claim 8 and the axiallyextending ribs in the closed end of said cap being of relatively shortlength with abutment forming inner ends which are spaced from the end soas to limit the axial movement thereof when the cap is telescoped overthe plug cover. and the rib on the cover is engaged in the groove in thecap.

References Cited UNITED STATES PATENTS 2,505,211 4/1950 Schiesel 40l-2l72,823,403 2/1958 Whitney 4O l213 2,923,957 2/ 1960 Gentile 401-2133,282,254 11/1966 Malrn et a]. 401-2l7 FOREIGN PATENTS 484,985 9/ 1953Italy.

LAWRENCE CHARLES, Primary Examiner

